The ability to deliver high doses of radiation to a tumor without significant damage to surrounding tissue would be a significant advancement in the radiation therapy of solid tumors. FeRx proposes to develop a convenient and safe regimen based on magnetic targeted delivery of radionuclides. Magnetic Targeted Carriers (MTCs) are 0.5 to 1.5 micron microparticles, composed of metallic iron and activated carbon. Using a small externally positioned magnet, MTCs are effectively targeted to a tumor where they are trapped. By irreversibly binding 188Re, a beta emitter radionuclide, to the activated carbon of the MTCs, tumor cells could be safely and effectively irradiated. The combination of a proven targeting technology with an effective radionuclide will lead to a product able to treat a wide variety of tumors in many different organs, with maximal radiation delivered to the tumor and minimal exposure to surrounding tissue. In this proposal we will investigate the feasibility of this project and we plan: 1) to develop and characterize radiolabeled MTCs for their labeling efficiency and labeling stability profile, 2) to evaluate the efficacy of their localization in a rat tumor model, and 3) to evaluate their biodistribution in a normal swine model. PROPOSED COMMERCIAL APPLICATION: Cancer remains one of the leading causes of death in developed countries. While therapies are overall more effective, there is still a tremendous need for less toxic and more effective treatments. The product FeRx proposes to develop would fulfill this need. It would also have a broad range of indications, such as pancreatic, liver, and lung cancers. Commercial opportunities would be very significant. In the lung cancer alone, there was an estimated 171,600 new cases in 1999.